Oncostatin M is a 28 KDa glycoprotein that belongs to the interleukin 6 (IL-6) family of cytokines which includes IL-6, Leukaemia Inhibitory Factor (LIF), ciliary neurotrophic factor (CNTF), cardiotropin-1 (CT-1) and cardiotrophin-1 like cytokine (See Kishimoto T et al (1995) Blood 86: 1243-1254), which share the gp130 transmembrane signaling receptor (See Taga T and Kishimoto T (1997) Annu. Rev. Immunol. 15: 797-819). OSM was originally discovered by its ability to inhibit the growth of the melanoma cell line A375 (See Malik N (1989) et al Mol Cell Biol 9: 2847-2853). Subsequently, more effects were discovered and it was found to be a multifunctional mediator like other members of the IL-6 family. OSM is produced in a variety of cell types including macrophages, activated T cells (See Zarling J M (1986) PNAS (USA) 83: 9739-9743), polymorphonuclear neutrophils (See Grenier A et al (1999) Blood 93:1413-1421), eosinophils (See Tamura Set al (2002) Dev. Dyn. 225: 327-31), dendritic cells (See Suda T et al (2002) Cytokine 17:335-340). It is also expressed in pancreas, kidney, testes, spleen stomach and brain (See Znoyko I et al (2005) Anat Rec A Discov Mol Cell Evol Biol 283: 182-186), and bone marrow (See Psenak O et al (2003) Acta Haematol 109: 68-75) Its principle biological effects include activation of endothelium (See Brown T J et al (1993) Blood 82: 33-7), activation of the acute phase response (See Benigni F et al (1996) Blood 87: 1851-1854), induction of cellular proliferation or differentiation, modulation of inflammatory mediator release and haematopoesis (See Tanaka M et al (2003) 102: 3154-3162), re-modeling of bone (See de Hooge A S K (2002) Am J Pathol 160: 1733-1743) and, promotion of angiogenesis (See Vasse M et al (1999) Arterioscler Thromb Vasc Biol 19:1835-1842) and wound healing.
Receptors for OSM (OSM receptor β, “OSMRβ”) are expressed on a wide range of cells including epithelial cells, chondrocytes, fibroblasts (See Langdon C et al (2003) J Immunol 170: 548-555), neuronal smooth muscle, lymph node, bone, heart, small intestine, lung and kidney (See Tamura S et al (2002) Mech Dev 115: 127-131) and endothelial cells. Several lines of evidence suggest that endothelial cells are a primary target for OSM. These cells express 10 to 20 fold higher numbers of both high and low affinity receptors and exhibit profound and prolonged alterations in phenotype following stimulation with OSM (See Modur V et al (1997) J Clin Invest 100: 158-168). In addition, OSM is a major autocrine growth factor for Kaposi's sarcoma cells, which are thought to be of endothelial origin (See Murakami-Mori K et al (1995) J Clin Invest 96:1319-1327).
In common with other IL-6 family cytokines, OSM binds to the transmembrane signal transducing glycoprotein gp130. A key feature of the gp130 cytokines is the formation of oligomeric receptor complexes that comprise gp130 and one or more co-receptors depending on the ligand (Reviewed in Heinrich P C et al (2003) Biochem J. 374: 1-20). As a result, these cytokines can mediate both the shared and unique biological activities in vitro and in vivo depending on the composition of the receptor complex formed. Human OSM (hOSM) differs from the other IL-6 cytokines in that it can form complexes with gp130 and either one of the two co-receptors, LIFR or the oncostatin receptor (OSMR). FIG. 27 illustrates the interaction between hOSM and gp130, LIFR and OSMR. The crystal structure of hOSM has been solved and shown to comprise a four α helical bundle with two potential glycosylation sites. Two separate ligand binding sites have been identified by site-directed mutagenesis on the hOSM molecule (See Deller M C et al (2000) Structural Fold Des. 8:863-874). The first, called Site II (sometimes “site 2”) interacts with gp130 and the second site, called Site III (sometimes “site 3”), at the opposite end of the molecule interacts with either LIFR or OSMR. Mutagenesis experiments have shown that the binding sites for LIFR and OSMR are almost identical but that a single amino acid mutation can discriminate between the two.
There is increasing evidence to support the hypothesis that modulating OSM-gp130 interaction may be of benefit in the treatment of RA and other diseases and disorders, particularly chronic inflammatory diseases and disorders such as osteoarthritis, idiopathic pulmonary fibrosis, pain, inflammatory lung disease, cardiovascular disease and psoriasis.
OSM is found in the SF of human RA patients (See Hui W et al (1997) 56: 184-7). These levels correlate with; the number of neutrophils in SF, levels of TNF alpha (sometimes “TNF”) in SF, and markers of cartilage destruction (Manicourt D H et al (2000) Arthritis Rheum 43: 281-288). Furthermore, the synovial tissue from RA patients secretes OSM spontaneously ex vivo (See Okamoto H et al (1997) Arthritis and Rheumatism 40: 1096-1105). It has also been demonstrated that OSM is present in synovial macrophages (Cawston T E et al (1998) Arthritis Rheum 41: 1760-1771) and as discussed earlier, OSM receptors and gp130 are expressed on endothelial cells, synovial fibroblasts, chonodrocytes and osteoblasts. Adenoviral expression of murine OSM (mOSM) in the joints of normal mice results in a severe inflammatory and erosive arthritis (See Langdon C et al (2000) Am J Pathol 157: 1187-1196). Similarly aggressive disease is seen in knockout mice lacking TNF, IL-1, IL-6 and iNOS following adenoviral mOSM delivery (See de Hooge A S K et al (2003) Arthritis and Rheumatism 48:1750-1761), demonstrating that OSM can mediate all embodiments of arthritis pathology. Mouse OSM expression using an adenovirally expressed mOSM vector causes damage to the growth plate typical of Juvenile Idiopathic Arthritis (See de Hooge A S K et al (2003) Arthritis and Rheumatism 48:1750-1761). In an experimental model of collagen induced arthritis, an anti-OSM antibody administered therapeutically to mice prevented all further progression of disease.
Similar results were seen when anti-OSM was administered prophylatically to mice with pristane induced arthritis, a relapsing/remitting model reminiscient of the human disease (See Plater-Zyberk C et al (2001) Arthritis and Rheumatism 44:
Osteoarthritis is a condition that affects the joints. There are three characteristics of osteoarthritis. It causes damage to cartilage—the strong, smooth surface that lines the bones and allows joints to move easily and without friction. It results in bony growths developing around the edge of the joints, and it causes mild inflammation of the tissues around the joints (synovitis). OSM has been demonstrated to play an important role in cartilage breakdown, inflammation and bone turnover and therefore blockade of this cytokine could play a role in the key aspects of disease pathogenesis. OSM acts synergistically with either IL-1 or TNF to induce collagenolysis in human nasal cartilage, involving loss of proteoglycans (PG) and collagen, the latter correlating with induction of MMP-1 and MMP-13. OSM with IL-1 will also induce PG loss from human articular cartilage, but the increase in collagen loss was not significant. (Morgan et al 2006) A number of studies using adenoviral vectors to increase joint cytokine concentrations have shown that OSM over-expression will induce inflammation, pannus formation, cartilage destruction and bone erosion. (Langdon et al 2000). Overall the literature suggests that OSM, particularly when combined with other cytokines, induces proteases that are involved in proteoglycan and collagen breakdown resulting in cartilage degradation and bone erosion.
Information from the literature suggests that OSM molecule may have some involvement in the inflammatory process associated with psoriasis. Work by Boifati et al (1998) has shown that spontaneous release of OSM is increased in organ cultures of psoriatic lesions, compared with non-lesional psoriatic skin and normal skin. (Kunsfeild et al 2004) Keratinocytes express the receptor for this molecule and in response to the ligand this causes keratinocyte migration and increases the thickness of reconstituted epidermis. Microarray analysis comparing the gene modulating effects of OSM with 33 different cytokines indicate that it is a potent keratinocyte activator and can act in synergy with pro-inflammatory cytokines in the induction of molecules such as S100A7 and β-defensin 2 expression, characteristic of psoriatic skin. (Gaze) et al 2006)
A role for OSM in inflammatory lung disease such as asthma and pulmonary fibrosis is also suggested from the literature. These diseases are characterized by an increased deposition of extracellular matrix (ECM), concomitant with proliferation and activation of sub-epithelial fibroblasts. OSM has been detected in the bronchoaveolar lavage fluid of patients during acute lung injury, particularly in cases of pneumonia (Grenier et al 2001).
OSM has been detected in the brains of MS patients, where it localises to microglia, astrocytes and infiltrating leukocytes (Ruprecht et al 2001). In addition, PBMCs isolated from MS patients spontaneously release more cytokines, including OSM, than cells from healthy controls and MS patients show a trend towards increased sera [OSM] (Ensoli et al 2002).
In addition to promoting inflammation in the brain, OSM may directly contribute to neurodegeneration, a feature of Alzheimer's disease, MS and of a subset of HIV patients. Monocyte supernatants from HIV patients' cause profound neuroblast growth inhibition and neuronal cell death. These effects were mediated by Oncostatin M in the culture supernatant (Ensoli et al 1999). Since many HIV patients suffer from brain atrophy caused by neuronal cell loss, OSM may be one mediator of this pathology.
Work by Tamura et al suggests that OSM may be involved in the development and maintenance of neuropathic pain (2003). Their studies revealed a subset of nociceptive sensory neurons that express the OSMβ receptor. All the OSMβR+ve neurons also expressed VR1 and P2X3 receptors, which have been shown to be crucial for development of both neuropathic and inflammatory pain (Jarvis et al 2002, Walker et al 2003). It has also been shown that the OSM−/−mouse showed reduced noxious responses to chemical, thermal, visceral and mechanical pain (Morikawa et al 2004). Interestingly, these animals have a deficit in VR1+, P2X3+ small sized neurons, but otherwise the animals appear normal.
A role supporting OSM in modulating the biology of cancer cells has also been suggested from the literature. OSM has been reported as having both growth stimulating and growth inhibitory properties in studies using tumour cell lines (Grant and Begly 1999). It is a potent mitogen for Kaposi's sarcoma derived cells (Miles et al 1992) and for myeloma cell lines (Zhang et al 1994). OSM decreases growth rates and increases differentiation in a number of tumour cell lines, including breast (Douglas et al 1998), and lung (McKormick et al 2000). However, whilst OSM may inhibit growth, at least in some breast carcinoma cell lines, it increases cell detachment and enhances the metatastic potential (Holzer et al 2004, Jorcyk et al 2006). OSM also upregulates expression and activation state of the hyaluronan receptor CD44, in some tumour cell lines (Cichy et al 2000), which is associated with tumour growth and metastasis (Yu et al 1997). In addition, the angiogenic properties of OSM and its ability to induce other angiogenic factors in some tumour cells (Repovic et al 2003), suggest that it could contribute to tumour angiogenesis in those tumours expressing OSM. The scientific literature suggests the OSM involvement in tumour biology but indicate the complexity. It is possible that OSM neutralisation could beneficial for treatment of some tumours. On the other hand, like TNF and IL-6 neutralisation, it carries some potential risk in others.
Evidence from literature suggests a potential role for OSM in cardiovascular disease. OSM is found in tissue macrophages in atherosclerotic lesions (Modur et al 1997) and as an angiogenic factor (Vasse et al 1999) may promote the neo-vascularisation characteristic of atherosclerotic plaques thought to contribute to vessel wall fragility. However, OSM also induces expression other angiogenic factors in endothelial cells; VEGF (Wijelah et al 1997) and bFGF (Bernard et al 1999). Interestingly, human endothelial cells have about 10-20 fold greater OSM receptor density than other cells (Brown et al 1991).
It is therefore an object of the present invention to provide a therapeutic approach to the treatment of RA and other diseases and disorders, particularly chronic inflammatory diseases and disorders such as osteoarthritis, idiopathic pulmonary fibrosis, cancer, asthma, pain, cardiovascular and psoriasis. In particular it is an object of the present invention to provide immunoglobulins, especially antibodies that specifically bind OSM (e.g. hOSM, particularly Site II thereof) and modulate (i.e. inhibit or block) the interaction between OSM and gp130 in the treatment of diseases and disorders responsive to modulation of that interaction.
In WO99/48523, we disclose the use of OSM antagonists in the treatment of inflammatory diseases and disorders. This disclosure used an anti-mouse OSM antibody in a murine model of arthritis.
All patent and literature references disclosed within the present specification are expressly and entirely incorporated herein by reference.
Nomenclature of antibodies—For the avoidance of doubt 15E10h and humanised 15E10 relate to the same antibody and are labelled Antibody X in some figures. Also 10G8/A9 and 10G8 relate to the same antibody.